Replace or take over maintenance of du, delayed and readfiletree

[vweevers]

No description provided.

[rvagg]

fixed by #649, #648, #647, they've come out of retirement

[vweevers]

Great. Should you need help maintaining these now or in the future, I'm willing.

As for delayed, which we only use here, we can replace that with an inline setTimeout() call, if we even still need a timeout.

[rvagg]

Ah, right, delayed@2.0.0 published, incoming via greenkeeper. Can be done without pretty easily but I always had a bit of a sweet spot for that package, especially its debouncer.

[vweevers]

Alright, we'll keep it, no need to refactor code that has worked for years.

I'm opening a PR though to fix a small bug I just found in that compression test. => #651